Solders are an important part of a packaged integrated circuit (IC). An IC die is often fabricated into a microelectronic device such as a processor. The solders complete couplings between the IC die and the outside world.
The increasing demands upon an IC to perform at high speeds and to not overheat presents problems for the solders. The increasing heat stresses in an IC package causes thermal stresses between the solders and the substrates to which the solders are bonded.